Issue Summary

The Macro module on Forge: Macro allows a function to be defined to be used in the property adfExoport and defines the export view of the macro, specified in Atlassian document format. 

When that function returns an ADF (Atlassian Document Format), using the node media: Node - media and in that media node, the attrs.type is defined to be 'external' depending on the size of the externally sourced image; the action to export the page where the macro is defined fails to properly load it before outputting the PDF document.

Steps to Reproduce

1. Create a Forge app using the macro module and define an adfExport function
2. Have the adfExport function return a structure that includes externally sourced images

   1. return {
         type: 'doc',
         version: 1,
         content: [
            {
               type: 'mediaGroup',
               content: [
                  {
                     type: 'media',
                     attrs: {
                         type: 'external',
                         url: '< insert here the externally sourced image>',
                     }
                },
                {
                   type: 'media',
                   attrs: {
                      type: 'external',
                      url: '< insert here the externally sourced image>',
                   }
                }  
               ]
            }
         ]
      }

1. Deploy and install the app in a Confluence instance, add that macro to a Confluence page, and export it to PDF.
2. If the images are large enough (over 2 or 3 megas), the generated PDF will contain a load spinner instead of the actual image.

Expected Results

The PDF export should have a mechanism that detects when the externally sourced images are fully received/loaded/rendered before outputting the PDF.

Actual Results

The generated PDF contains load spinners instead of the actual content.

Workaround

Currently there is no known workaround for this behavior. A workaround will be added here when available